lyca-lightweight-carrier-assistant

LYCA (after Laika the Russian astronaut dog) is a spherical Lightweight Carrier Assistant drone to be used in zero gravity inside the International Space Station. It is capable of carrying small objects with a mass no greater than 5 lb (2 Kg) from one place of the ship to another, in a completely autonomous way upon the astronaut’s request.

We defined three main design criteria for this challenge: size, energy consumption, and compatibility with inhabited spaces. Having as a main to maintain the lowest energy consumption.

Having that clear, we evaluated several shapes. Our analysis has showed that in shared spaces an spherically shaped drone would have no sharp edges that could greatly harm humans or equipment onboard the ship.

The drone’s sphere is divided in two hemispheres. The top one houses the electronic brains and the lower one is used to store the objects to be transported. This lower hemisphere is divided in 5 blades that are opened whenever an object needs to be put inside to outside. A retrieval 5-blade claw is located inside of the storage section to help retrieve the load. In the prototype we only created the 5 blades controlled by 5 micro servos. At around 11.81 - 15.75 in (30 – 40 cm) of diameter, the ship provides 862.70 – 2,044.92 in3 (14,137.16 – 33,510.32 cm3)

In regards to breaking inertia and inducing movement several approaches were analyzed: flywheel mechanism, compressed gas propulsion and regular air rotors propulsion.

The first one was discarded because our tests could not prove a displacement motion was happening. The second one, and preferred jetpack thrust method used in outer spaces was also discarded because small compressed nitrogen canister would require regular recharging, replacing, stocking and sourcing.

This led us to use brushless motors. But we wanted to use the less amount of rotors we could, so we designed a 2-turbine system with a connected hoses to deliver thrust to 5 point distributed volumetrically among the sphere. Actuators would control the valves to distribute air. This system utilizes minimum thrust to move and corrects direction on the fly, which translates in less energy consumption. For prototyping purposes we used 2 DC motors with 4 halve-spoon plastic blades mounted on a servo each one (one for the X-axis with rotational horizontal motion and one for the Y-axis with rotation vertical motion).

The original design includes ultrasonic sensors to help the drone navigate around the spacecraft and to avoid collisions with incoming or unexpected objects. A gyroscope was also included to provide the drone with spatial stability. A flywheel is also needed to compensate the action of the drone with the data received from the gyroscope. For prototyping purposes none of this features were included.

Assuming we have access to, we are proposing to use the cameras inside the spaceship to combine with the reference points stored in the drone to generate spatial location data. This will be used for navigation, stability and safety of the drone within the facilities. It would also allow astronauts to send or call the vehicle on demand to any place they or the object to be retrieved or delivered are located inside the spacecraft. If we can use the onboard computer system to unload data processing on the drone it would help in lowering the energy consumption.